A really good mild method for oxidising benzylic and (some) allylic alcohols to aldehydes is refluxing over active Manganese Dioxide in chloroform or DCM. Just filter through Celite for work-up.
For me, MnO2 sometimes do not work, because it tend to oxidize electron-rich benzene derivatives, mainly to quinones or some polymeric junk. PIDA is a reagent of choice for me, combined with TEMPO or somtimes it works also without it.
I think because that system regenerates Ca(BH4)2 that can reduce an ester functional group? Like “That Chemist” said, NaBH4 can sometimes reduce the ester (either by nuking more equivalents, or adding other additive stuff, choosing the right solvents, temperature, etc).
@@That_Chemist Thanks alot, I really like the insight you are giving in the more practical aspects, such as this and that a compound smells too bad. I find that is typically lacking in the text books :)
I flunked out of college because of organic chemistry II. I don’t want to give up on the science because it’s important to me, but the way it’s taught is really unintuitive. with only showing the theoretical mechanisms which we’re taught to draw by pen and paper so that’s quite frustrating. It’s a lot to ask for but… If you could curate a series of photo/video to accompany the steps of each mechanism in the lecture, that would be a legendary achievement. Anyways, thanks for all the effort you put into these and keeping a flunk like me interested.
@@That_Chemist I was thinking that when explaining a reaction, that a real life example of the reaction should be accompanied with the electron pushing arrows. I always found that learning Ochem by only seeing electron pushing arrows was too abstracted from reality. The reality of each reaction is that the equipment necessary to carry out the reaction is chosen carefully. Almost all of the reactions I was taught in school were simply on paper, I felt that my intuition was lacking because out of the hundreds of reactions I dealt with from textbooks and lectures, only a few were actually taught with real glassware and machinery; those being the labs. A good example of what I wish I had would be Extractions&fire/ire method of teaching reactions, who records what he does and explains the set up. I’m able to visualize the reaction more intuitively. I’ve seen on the subreddit r/chemhelp many posts of students being given practice problems or textbook examples where the reaction or characterization of the chemical properties in question are in someways not representative of their actual value to achieve their intended results. That they lead students astray and perhaps even ill prepared to do it in more practical ways. To put it in another way as an analogy, I wish that chemistry was taught more like a TV cooking show with the cookbook to follow in writing. Does this make sense?
A really good mild method for oxidising benzylic and (some) allylic alcohols to aldehydes is refluxing over active Manganese Dioxide in chloroform or DCM. Just filter through Celite for work-up.
True!
For me, MnO2 sometimes do not work, because it tend to oxidize electron-rich benzene derivatives, mainly to quinones or some polymeric junk. PIDA is a reagent of choice for me, combined with TEMPO or somtimes it works also without it.
13:14 I expect dimethyl sulfide to smell way nicer than you have described. I think it will smell like seaweed, which is nice to me.
Chloromethyl methyl sulfide is even worse 💀
Hey just to confirm, is that sigmatropic rearrangement in the Swern Oxidation mechanism a [1,3] sigmatropic hydrogen migration?
I did some reactions in the lab where i used NaBH4 with CaCl2 and it was able to reduce esters to alcohol, do you know why it works?
sometimes NaBH4 can reduce esters, but it is typically case-by-case
I think because that system regenerates Ca(BH4)2 that can reduce an ester functional group?
Like “That Chemist” said, NaBH4 can sometimes reduce the ester (either by nuking more equivalents, or adding other additive stuff, choosing the right solvents, temperature, etc).
First of all, thanks for the great content! - is there any rule of thumb regarding when to use DMP or Swern-oxidation?
Both are equally acceptable - it depends on lots of factors; Swern is dirt cheap, DMP is not dirt cheap
@@That_Chemist Thanks alot, I really like the insight you are giving in the more practical aspects, such as this and that a compound smells too bad. I find that is typically lacking in the text books :)
@@pellehansen8929 usually people have dedicated fumehoods for those reactions - they can be unpleasant
I flunked out of college because of organic chemistry II. I don’t want to give up on the science because it’s important to me, but the way it’s taught is really unintuitive. with only showing the theoretical mechanisms which we’re taught to draw by pen and paper so that’s quite frustrating.
It’s a lot to ask for but… If you could curate a series of photo/video to accompany the steps of each mechanism in the lecture, that would be a legendary achievement.
Anyways, thanks for all the effort you put into these and keeping a flunk like me interested.
what are you interested in seeing a photo/video of?
@@That_Chemist I was thinking that when explaining a reaction, that a real life example of the reaction should be accompanied with the electron pushing arrows. I always found that learning Ochem by only seeing electron pushing arrows was too abstracted from reality. The reality of each reaction is that the equipment necessary to carry out the reaction is chosen carefully. Almost all of the reactions I was taught in school were simply on paper, I felt that my intuition was lacking because out of the hundreds of reactions I dealt with from textbooks and lectures, only a few were actually taught with real glassware and machinery; those being the labs.
A good example of what I wish I had would be Extractions&fire/ire method of teaching reactions, who records what he does and explains the set up. I’m able to visualize the reaction more intuitively.
I’ve seen on the subreddit r/chemhelp many posts of students being given practice problems or textbook examples where the reaction or characterization of the chemical properties in question are in someways not representative of their actual value to achieve their intended results. That they lead students astray and perhaps even ill prepared to do it in more practical ways.
To put it in another way as an analogy, I wish that chemistry was taught more like a TV cooking show with the cookbook to follow in writing.
Does this make sense?
@@XxfishpastexXno, arrow mechanisms make sense